Headlight bulb



Aug. 10 1926. 1,595,535

W. H. WOOD HEADLIGHT BULB Filed Sept. 2, 1925 I William H Wood ink/Mao? UNITED STATES PATENT OFFICE.

\llTIl'aLIAlllI H. WOOD, OF SOUTH EUCLID, OHIO.

HEADLIGHT BULB.

I Application filed September 2, 1925. Serial No. 53,995.

This invention relates to electric headluminous. I prefer a length of manganin light bulbs and has for its object the proor constantin wire but any common successvision of a new and improved dimming exful resistance wire can be used which will pedient. It is well known that the laws of not melt below a red heat. Theresistance 6 many municipalities as. well as a just conand carrying capacity of the wire depends 60 sideration for the comfort of other people upon the voltage of the circuit, the material, requires the employment of a less intense size, and candlepower of the main flament, light inside cities and villages than is do and the candlepower desired after dimming. sirable when driving in the open country. The ordinary 21 c. p., 68 volt headlight,

The objects of my invention are the provifor example requires a resistance not over 65 sion of a dimming expedient which shall be about 1 ohm nor much under ohm, which cheaper in cost and more reliable in operamay be secured by using from about 6 to tion than previous devices; the provision of centimeters of No. 30 gauge (B. & S.) cona dimming lamp of single filament type stantin or manganin wires, spot welded to- 1 which can be used in a double circuit systhe leading-in wires. If other voltages, 7 term; the provision of a lamp bulb of this candlepowers, or resistance materials are used nature which can be made and sold more other sizes and lengths of wires must be emcheaply than other bulbs designed for this ployed. In any case the wire is so disposed purpose and substituted for them without as not to impede its introduction into the v2 changing the equipment in other regards; globe. Such wires can easily be looped 7 while further objects will appear as the dearound the leading-in wires as shown 1n scription roceeds. Figs. 1 and 2. The large size of the resist- In the rawing accompanying and form anoe element prevents its becoming overing a part of th1s application Fig. 1 illusheated even in a vacuum lamp.

trates a simple form of automobile head- Such a lamp is employed in the usual cir- 80 light lamp together with a diagram of a cuit shown diagrammatically in Fig. 1 comcommon wiring arrangement with which the prising a socket 12 which is generally same may be employed; and Fig. 2 is a secgrounded to the frame of the machine, a battional view corresponding to the lines 2-2 tery 13 having its negative pole similarly of Fig. 1. grounded to the frame of the machine, and

My improved lamp comprises the usual a suitable switch 14. of any desired construcglass globe 1, closed at one end by the usual tion connected to the positive pole of the press-tube 2 in which are sealed three leadbattery and adapted to be turned selectively ing-in wires-3, 4, and 5, a luminous filament to the points 15 or 16 which are suitably 35 6 of any suitable or desired shape and maconnected to terminals in the socket en- 0 terial bein carried by the leading-in wires gaged by the contacts 8 and 9 respectively.

3 and 4. ecured to the closed end of this My improved lamp is susceptible of very globe is the metal base 7 provided with two cheap and ready manufacture owing to the contacts 8 and 9 insulated from the base fact that the resistance wire 10 is much and from each other. In the present emcheaper than filament wire and can be lo- '95 bodiment I have shown the leading-in wire cated in place and spot welded to the leading- 4 as grounded to the base 7 the leading-in in wires without the necessity of accurate wire 3 as connected to the contact point placing. The lamp 1s free from deteriora- 8, and the leading-in wire 5 connected to the tion since this wire is preserved out of concontact point 9. tact with the air and being strong and rug- 10 Connected to the leading-in wires 3 and ged is not subject to acc dental breakage.

5 inside the lamp bulb is a wire 10, prefer- Having thus descrlbe'd my invention ably of a materlalhaving rather'high spewhat I claim is: a cific resistance so that it can be made of 1. In an automobile headlamp bulb, the

.9 fairly substantial size and strength. Its combination with a. globe and a filament size and length are so chosen, as coupledwith therein, of two circuits lncludmg said fila: its specific resistance, to limit, the current ment, a coil of non-lumlnous resistance wire when connected in' series with the filament inside said globe constituting apart of one 6 to reduce the candle power thereof to the circuit, said coil having su cient size and 5 desired degree without itself becoming dissipat ng power to dim said filament without itself becoming incandescent, and exglobe and connected between said last named ternal connections for said circuits carried leading-in wires, and a light-emitting filaby the base of said lobe. ment connected between one of said last 2. In an automobile headlamp bulb, the named leading-in Wires and said first named 15 5 combination with a glass globe and a metal leadlng-in wire, said coil having suflicient base secured thereto, said base also having size and dissipating power to dim said filatwo contacts insulated from said base and ment without itself becoming incandescent. from each other, of three leading-in wires In testimony whereof I hereunto aflix my sealed in said globe and connected, one to signature. 0 said base and one to each of said contacts, I a coil of resistance wire located inside said WILLIAM H. WOOD. 

